If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Or certainly heard, unless they are also using sound-reduction charms.

There are also super-sensitive metal detectors, assuming most wizards might be wearing a necklace, watch, or belt of some sort, not to mention whips and chains if they are Dark wizards.

And of course, don't forget lasers. I bet they can do just about anything, and considering you can get laser pointers for less than ten dollars on Amazon, I'd carry one around with me just in case I smelled something funny.

Muggles Detecting Invisible Wizards

Assuming you have your standard Voldemort fights the Muggle World scenario, how could Muggles, assuming they know that wizards can turn invisible, go about detecting them?

I have some ideas, but I'd like to hear your input and suggestions.

Dogs
Neither Invisibility Cloaks nor Disillusionment Charms do anything to block scent or sound, and most wizards would probably not think to mask these signs. A well-trained dog might be able to smell or hear an invisible intruder and bark to alert its handlers of the invisible wizard's presence. Unfortunately, this doesn't let the Muggles see the wizard; it only lets them know they might be in the area. Dogs could also be easily distracted.

At least this method would be cheap and easy, and should provide a minimum of detection.

Infrared Imaging
Invisibility Cloaks and Disillusionment Charms do nothing to hide the wizard's body heat, and having wizards charm themselves to be the same temperature as their surroundings sounds like something they'd never think to do. So even if a wizard is invisible in the visible light spectrum, he can still be seen through an infrared camera as a bright red-yellow figure against a blue-ish background. If a soldier has goggle-mounted infrared imaging, he can see the invisible wizard through IR and shoot at him. This sounds to me like the most precise method of invisible-wizard detection, but also very expensive and uncommon, as IR imaging isn't cheap.

Shadows
The Disillusionment Charm is a sort of active camouflage rather than true invisibility, which means that someone who is using the charm will still cast a shadow. Seeing a disembodied shadow walking around would tip off anyone who notices that there is an invisible wizard there. Unfortunately, this method depends on Muggles being very observant, and it is useless at night or against wizards using Invisibility Cloaks. Still, at least it's something anybody can do on their own.

Tripwires
Very thin tripwires attached to directional mines or guns should take care of any invisible wizard who isn't watching his step. The triggering mechanisms can also be very sensitive in order to also go off in case the wires lose tension, which would happen if the intruding wizard cuts or vanishes the wires. Unfortunately, this method sounds rather dangerous and hard to set up, so it would probably be limited to heavily protected installations guarding, say, the Royal Family.

Silly String
Funnily enough, US and British soldiers in Iraq have been using Silly String to detect thin tripwires, in which the settles on the wire, revealing them. The same thing could be done against an invisible wizard. This method is limited by the very short spray range of the aerosol can, the Muggle wielder being alert enough to suspect there may be an invisible intruder to spray at in the first place, and the invisible intruder being very cooperative by standing close and still enough to get sprayed. At least Silly String is comparatively cheap, and it's better than nothing.

Sprinklers, Hoses, and Miscellaneous Liquids
Applying the same logic as the Silly String, water from sprinklers or hoses would splash off an invisible wizard and soak his clothing. Even better, bright paint could be sprayed, making the wizard much more visible if it were to get on him. Any continuous sprinkler-based wizard detection however, would require an awful lot of water or paint, and it can only be used at fixed locations. Manned hoses attached to fire engines could provide some mobile detection, but like many of these methods, it depends on the wielders being alert and spraying anything suspicious. Water balloons filled with paint are another possibility.

Those are some methods I've thought of off the top of my head. Does anyone have any other ideas?

Seventh Year
GryffindorBeing Chased by Singing Dwarves with Valentines

Join Date

Aug 2010

Location

Behind my piano

Posts

701

Well, they could simply go around with their arms out in front of them feeling for them, though I doubt this would be effective, as a wizard would simply sidestep them or Avada Kedavra them on the spot (as I'm sure they would do if someone was about to spray something at them).

Radar could also be highly effective, as it is done through echolocation, and being invisible does not make you not solid. This would be a very expensive investment for Muggles though.

Also, perhaps the Muggle has a 'Sixth Sense' and can just feel when someone is behind them.

Muggles could also have the misfortune of simply running into the wizard because both the Muggle and wizard are completely ignorant of their surroundings.

Scent would of course be effective, as Gina has stated. Perhaps the witch wears perfume. Or suppose it's Mundungus. You would certainly smell him. And as Gina has stated, being invisible does not make you silent - how shortsighted being invisible can make us!

There are also super-sensitive metal detectors, assuming most wizards might be wearing a necklace, watch, or belt of some sort, not to mention whips and chains if they are Dark wizards.

And of course, don't forget lasers. I bet they can do just about anything, and considering you can get laser pointers for less than ten dollars on Amazon, I'd carry one around with me just in case I smelled something funny.

Metal detectors could be useful for installations, but they're not exactly handy or portable.

Lasers would go right through someone wearing an invisibility cloak, but they would appear on someone under a Disillusionment Charm, since they are magically camouflaged and not truly invisible. Fortunately, most wizards seem to rely on Disillusionment in canon.

How much did laser pointers cost around 1997-1998?

Of course, simply spotting an invisible wizard with a laser pointer is not enough. Mounting it as a laser sight on a rifle on the other hand...

Originally Posted by Maple_and_PheonixFeather

Radar could also be highly effective, as it is done through echolocation, and being invisible does not make you not solid. This would be a very expensive investment for Muggles though.

Dang. I knew I was forgetting something. As you said, anything that is solid will appear on radar. Unfortunately, it would be fairly useless on the ground with so much clutter, so it would be limited to scanning the skies for wizards on broomsticks.

Unfortunately, the UK doesn't field any radar-guided anti-aircraft guns anymore – they rely exclusively on missiles nowadays. Shooting a flying wizard with a surface-to-air missile would be complete overkill and unnecessarily expensive, but it would at least get the job done.